Application of Carbon Paste Electrodes Modified with Imprinted Zeolite X as Potentiometric Sensors for Amitriptyline Analysis in Pharmaceuticals

Carbon paste electrodes have been developed to improve the performance and selectivity of electrodes for the potentiometric analysis of amitriptyline (AMT). Carbon paste electrodes modified with imprinted zeolites (IZ) were developed as potentiometric sensors for AMT analysis. In this study, zeolite X was synthesized using Na2O, Al2O3, SiO2, and H2O at a mole ratio of 4.5: 1: 3: 315. The IZ was synthesized by adding AMT to the mixture at an AMT/Si molar ratio of 0.0306 as a template. Subsequently, AMT was extracted from the zeolite framework to form active and selective AMT recognition sites. The optimum performance was achieved by the electrode composed of activated carbon, paraffin, and IZ at a composition of 12:7:1, which was expressed by a Nernst factor of 28.38 mV/decade, measurement range of 10-5–10-2 M with a correlation coefficient of 0.9994, and a low detection limit of 1.15 × 10-5 M. The detection limit can accommodate the lower dose of AMT in pharmaceuticals. The modified electrode had precision of 97.5–99.9% and accuracy of 91.2–107%, with a response time of 24–211 s. Moreover, it was stable for four weeks after more than 100 uses. Application of the modified electrode in the determination of AMT in three pharmaceutical samples resulted in a 96–102% recovery. The presence of glucose, lactose, mannitol, and ZnSO4 had no effect on the potentiometric analysis of AMT using the modified electrode. The excellent analytical performance of the modified carbon paste electrode suggests its potential applications in the analysis of AMT, an affordable medicine.